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J Dutton

Publications and source records attributed to J Dutton.

At least 19 recordsLinked to original sources
PubMed1992

Regional distribution of ECS in contractile and conductive elements of rat and rabbit heart.

By adaptation of recently developed quantitative microanalytic techniques, the size of the extracellular space (ECS) was measured regionally in the rat and rabbit cardiac conductive and contractile tissues. When inulin and sucrose were measured as extracellular markers in rabbit heart, the ECS in the atrioventricular (AV) node was found to be, respectively, 2.4 and 2.2 times larger than that of adjacent ventricular muscle. By use of inulin, the ECS in the rabbit His bundle was found to be 1.8 times larger than the adjacent ventricular tissue. Similarly, when inulin was used in rat, the ECS of the AV node, His bundle, right bundle branch, and right atrium was found to be, respectively, 2.5, 1.9, 1.8, and 1.2 times larger than that of left and right ventricular muscle. Similarly, significant regional differences in ECS were also observed in rat heart with sucrose. By use of glucose as an ECS marker, these results also revealed a 2.5-2.9 times larger ECS in rat and rabbit AV node compared with contractile elements. In contrast, ATP content, measured as an intracellular marker, was the same in both AV nodal and ventricular muscle tissue from both rat and rabbit. These data demonstrate that there are significant regional variations in ECS within the cardiac conduction system. Collectively, the data obtained with all extracellular markers indicate that the size of the ECS of the conduction system is markedly larger than the adjacent contractile muscle.

Adenosine Triphosphate↗
PubMed1992

Pyrophosphate in synovial fluid and urine and its relationship to urinary risk factors for stone disease.

Inorganic pyrophosphate (PPi) measurement in urine and synovial fluid has been established using the PPi-dependent phosphorylation of fructose-6-phosphate and subsequent reduction of dihydroxyacetone phosphate by NADH. The assay is linear up to 200 mumol/L, easy to perform and gives results comparable to more complex methods. Daily urinary output of PPi was independently related to both age (P = 0.0014) and sex (P = 0.0002). Men had higher values than women and older individuals excreted greater amounts. Male stone formers, younger than 45 years, had lower values than age matched male controls (P = 0.012). Younger female stone formers also tended to have lower values. In stone formers' urine significant and independent correlations were found of PPi excretion with urine volume (P = 0.004) and with phosphate excretion (P = 0.008). Oxalate excretion and that of other urine constituents and the degree of supersaturation with common stone-forming salts were not correlated with PPi. PPi excretion was markedly elevated in the urine of two patients with hypophosphatasia. The PPi concentration in synovial fluid from painful, swollen knee joints was elevated, but unrelated to the presence or absence of PPi or urate crystals.

Adolescent↗
PubMed1991

Measurement of extracellular space in the rabbit AV node.

We used quantitative histochemistry to measure the size of the extracellular space (ESC) in various regions of the rabbit heart. When inulin, sucrose, and sorbitol were used as ECS markers, the ECS of the AV-nodal tissue was found to be, respectively, 2.4, 2.2, and 2.5 times larger than that of left ventricular muscle. Glucose was also measured over a 50-fold serum concentration range as an extracellular marker for AV-nodal tissue, left ventricular muscle, and Purkinje fibers. Measurements with glucose also revealed that the ECS of the AV node was 2.5-2.8 times larger than that of ventricular muscle. In contrast, the ECS of the AV node was the same as that of Purkinje fibers when glucose was used as an extracellular marker. ATP content, measured as an intracellular marker, was similar in both AV-nodal and contractile tissue. Collectively, the data obtained with all extracellular markers indicate that the ECS of the AV-nodal region is approximately 2.5 times larger than that of adjacent contractile tissue. Differences in the size of the ECS in various regions of the heart probably have functional significance and should be considered appropriately during the interpretation of data obtained by biochemical and densitometric approaches.

Acetylcholinesterase↗
PubMed1990

Determination of total body calcium by prompt gamma neutron activation analysis: absolute in vivo measurements.

Sequential TBCa measurements using the prompt gamma ray technique are firmly established and a number of patient groups are under investigation. A technique has been proposed for the absolute measurement of TBCa based upon the use of TBCl as an internal standard. Further work is needed to establish the validity of the method, but the initial results are encouraging.

Body Composition↗
PubMed1989

The effect of subliminal oedipal and competitive stimulation on dart throwing: another miss.

Silverman and his associates have reported that subliminal presentation of oedipally relevant competitive stimuli can modify dart-throwing performance in male subjects. This study replicated their paradigm, but also examined the effects on performance of nonoedipal competitive stimuli. Our results failed to support Silverman's. Both types of subliminally presented competitive stimuli failed to have any systematic effect on dart-throwing performance.

Adolescent↗
PubMed1989

Calibration and evaluation of a 252Cf-based neutron activation analysis instrument for the determination of nitrogen in vivo.

A novel clinical instrument for multi-element in vivo neutron activation analysis has been recently constructed in Swansea. The instrument is intended primarily for prompt gamma measurement of total and partial body calcium, total body nitrogen and partial body cadmium. For the measurement of nitrogen the subject is scanned both prone and supine across a vertical collimated neutron beam from a 4 GBq 252Cf source. Two shielded Nal(TI) detectors, each of volume 2760 cm3, are placed above the subject on the opposite side to that irradiated. The prompt gamma ray spectrum contains prominent peaks from hydrogen, nitrogen, chlorine and carbon. The optimisation, calibration and evaluation of the instrument for the measurement of nitrogen, by the reaction 14N(n, gamma)15N, is described. The calibration corrects the ratio of nitrogen-to-hydrogen counts measured from the subject for background gamma rays and the effects of body habitus. Body hydrogen is use as as internal standard. Repeated measurements of a homogeneous anthropomorphic phantom indicate that the ratio of nitrogen-to-hydrogen counts may be determined by a coefficient of variation of 1.6% for a neutron dose equivalent incident on the phantom of 0.45 mSv (QF = 10). The accuracy of the calibration was assessed by measuring three anthropomorphic phantoms (weight range: 41.4-110 kg) containing simulated skeletons and the major organs of the body. For these phantoms the mean discrepancy of the measured to the known nitrogen content was +4.9%. The simultaneous measurement of chlorine and carbon is discussed.

Activation Analysis↗
PubMed1988

Prostacyclin: a new treatment for vasospasm associated with subarachnoid haemorrhage.

One of the major problems associated with the treatment of ruptured intracranial aneurysms is the syndrome of late onset ischaemia. Patients so affected deteriorate neurologically and cerebral angiography often shows narrowing of the intracranial arteries, commonly known as vasospasm. Many drugs have been used to treat the condition but with little success. A new group of compounds have come into clinical use recently, the Prostaglandins. One member, Prostacyclin (PGI2 or Epoprostenol) is claimed to be one of the most potent vasodilators known. It was used at Manchester first on an experimental model. An isolated piece of human basilar artery was caused to contract using various agents. Prostacyclin was then used in an attempt to relax the contracted segment of artery. It, surprisingly, caused profound relaxation at very low concentrations of Prostacyclin, yet at higher concentrations it again caused the artery to contract. A literature search suggested this also was seen in the living subject and the crossover occurred at a dosage of 5 ng/kg/min. A limited pilot trial was therefore devised using Prostacyclin at the low concentration of 1 ng/kg/min and used on six patients. Patients were assessed, in the main, for clinical improvement and change in radiological spasm. Clinically, the results exceeded our expectations in that all patients improved, some back to normal. Radiologically, the vasospasm changed but did not revert completely and also unusual extracranial-intracranial anastomoses appeared in the angiograms. In addition, in one patient, cerebral blood flow showed a more than threefold increase. No generalised cardiovascular collapse occurred and no bleeding tendency was observed.

Epoprostenol↗
PubMed1987

A clinical instrument for multi-element in vivo analysis by prompt, delayed and cyclic neutron activation using 252Cf.

The design and construction of a versatile clinical instrument for multi-element in vivo neutron activation analysis of major and minor body elements is described. A 200 micrograms (4 GBq) 252Cf neutron source is stored below ground level and pneumatically propelled to one of two irradiation ports. These deliver collimated beams of fast neutrons either to a localised volume such as the liver or kidney, or across the width of a patient for a head-to-toe scanning whole-body measurement. The source control system allows selection of either a continuous or cyclic mode of activation. The instrument is intended primarily for measurement, by the prompt-gamma technique, of total and partial body calcium, total body nitrogen and partial body cadmium. The potential of the instrument for determination of these three elements has been established. Phantom results suggest that total body calcium can be measured with a precision of +/- 2.6% (CV) for an average whole-body skin dose equivalent of 6.4 mSv; total body nitrogen with a precision of +/- 2.0% for an average whole-body skin dose equivalent of less than 0.4 mSv; and a detection limit (2 SD of the background) of 2.4 mg of cadmium in the kidney has been obtained for a radiation dose equivalent to the skin of 3 mSv (QF = 10). The suitability of this instrument for the measurement of other elements is also discussed.

Californium↗
PubMed1985

A feasibility study for the in vivo measurement of beryllium by photonuclear activation.

Diagnosis of the beryllium-induced disease, berylliosis, is often difficult and always requires that the presence of the metal in tissue be demonstrated. The feasibility of developing an in vivo method of measurement, which exploits the uniquely low photonuclear reaction threshold of 1.67 MeV in beryllium, has been investigated. Suitable photon sources and detector systems were assessed, both experimentally by phantom studies and theoretically by use of a Monte-Carlo neutron transport code. It is concluded that by using a filtered source of 124Sb for bilateral irradiation of the chest, and an array of twenty BF3 counters, beryllium could be measured to an accuracy of 0.33 mg per lung, which corresponds to a 2 SD detection limit of 0.67 mg, for a skin dose of 50 mGy delivered within a period of 90s. Such a facility would be capable of contributing to the aetiology of the disease in a large proportion of cases, but the wider use of the method for screening exposed workers would require further improvements in detection efficiency.

Beryllium↗
PubMed1978

Intracranial solitary chondroma. Case report.

A case of massive solitary intracranial chondroma involving the base of the skull in a 15-month-old baby boy was successfully treated by total excision. The diagnosis was greatly simplified by the us of computerized tomography, which materially helped in planning the surgical approach.

Brain Neoplasms↗
PubMed1978

Hodgkin's disease.

Explore the source record for details and available documents.

Hodgkin Disease↗
PubMed1975

Prognosis in colon cancer: a pathologic reassessment.

One hundred forty-eight cases of colon carcinoma were subjected to further pathologic study. Survival was correlated with stage and grade of the tumor and with the number of involved lymph nodes. In addition, cases were assessed as to the extent of local chronic inflammatory reaction about the lesion and the degree of sinus histiocytosis in draining lymph nodes. A correlation was possible between grading, staging, extent of lymph node involvement, and survival. A substantial difference in five-year survival was shown when local inflammatory reaction was present and when sinus histiocytosis was observed. The presence of both of these factors further improved survival. An adequate evaluation of these factors, both individually and in combination, should improve our ability to assess prognosis in colon cancer.

Adenocarcinoma↗